The proposed research will conduct the first ever dose-determination trial of a behavioral intervention to improve engagement in HIV care, antiretroviral therapy (ART) adherence and HIV viral suppression. The trial is designed to inform the implementation of behavioral interventions, including several in CDC’s Compendium of Evidence-Based Interventions. Behavioral counseling has the flexibility and reach to overcome numerous challenges to HIV care, including social, emotional, and structural barriers. However, basic questions of how to best implement and scale-up interventions remain unanswered, such as “how much intervention is needed to achieve HIV suppression in subgroups of patients facing individual and social challenges?” There are currently no dose-determination trials in the HIV behavioral intervention literature to guide implementation decisions and health service policy. In the proposed research we specifically aim to: (a) determine the minimum effective dose of an evidence-based HIV treatment engagement and adherence intervention, (b) identify subgroups of patients requiring greater and fewer intervention resources to achieve and sustain viral suppression, and (c) the costs associated with intervention dose-response. Participants who are receiving ART and confirmed HIV unsuppressed (>200 copies/mL) will be randomized to either: (a) the dose determination condition of weekly evidence-based behavioral self-regulation counseling until achieving HIV suppression (<200 copies/mL), or (b) fixed dose 5-weekly sessions of evidence-based behavioral self-regulation counseling sessions. The dose determination condition adjusts to patient needs and determines the dose to achieve HIV suppression, in contrast to the fixed dose condition that does not adjust to patient response. The trial is therefore designed to determine the number of behavioral counseling intervention sessions needed to achieve and sustain HIV suppression. Once viral suppressed, counseling in the dose-determination condition is suspended. In contrast, the fixed-dose condition is delivered in five prescribed sessions as disseminated by the CDC. Follow-up assessments commence for 12-months from baseline with the primary endpoint of 12-month blood plasma HIV viral load and secondary outcome of ART adherence. Response to counseling is defined by achieving viral suppression (<200 copies/mL) and non-response is defined by not achieving viral suppression (>200 copies/mL). Participants in both the dose-determination and fixed-session conditions who initially respond and rebound to unsuppressed viral load will receive additional counseling with redose-response monitored and analyzed. Longitudinal analyses will examine intervention dose for key patient subgroups and dose-response cost-effectiveness analyses to guide resource allocation and implementation decisions. This research is aimed at informing health policy makers and programmatic decisions regarding intervention implementation to inc...